Visit all of Peru with your family! For small children, we recommend "Cusco and the Amazon". For families with children ages 6 and up, you can visit Machu Picchu by train, the Amazon Jungle (Tambopata and Manu National Park).
For families with active teenagers, we recommend the famous Inca Trail, Salkantay Trek, Lares Trek and Huchuy Qosqo Trek, Lake Titicaca, Colca Canyon, Machu Picchu & Huayna Picchu, and the Ballestas which are an excellent spot to see marine life.
Travelling with chlldren in high altitude: Keep in mind that it's more difficult to notice the effects of altitude sickness in children. Some of the symptoms include: loss of appetite, headache, dizziness, nausea, vomitting, and physical exhaustion. The children should watch their children closely to recogize these symptoms. Some prevention tips include drinking coca tea and lots of water during the day.